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Rare earth Er contained SnZn based leadless solder and its preparation method

A lead-free solder and rare earth technology, applied in welding equipment, manufacturing tools, metal processing equipment, etc., can solve the problems of not being suitable for large-scale use, increasing the crystallization temperature range, reducing the plasticity of solder joints, etc., and improving the spreading process Effects of performance, microstructure refinement, and increased purity

Inactive Publication Date: 2005-06-01
BEIJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, too much Bi will increase the crystallization temperature range, which may cause thermal cracks in solder joints or reduce the plasticity of solder joints.
In addition, In is a rare metal with a low abundance in the earth's crust and is expensive, so it is not suitable for large-scale use

Method used

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  • Rare earth Er contained SnZn based leadless solder and its preparation method
  • Rare earth Er contained SnZn based leadless solder and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0022] Example 1: 26 grams of potassium chloride and 20 grams of lithium chloride mixed salt were melted at 460°C and poured on 94 grams of tin. Raise the temperature of the furnace to 620°C to melt the tin and the mixed salt, then add 5 grams of Zn to the tin liquid while stirring continuously to form an alloy; use a stainless steel bell jar with holes on the wall to quickly press 1 gram of rare earth Er into the Among the above molten alloys, and keep stirring until the rare earth is completely melted. Keep warm for 1 hour, stirring constantly to homogenize the alloy. Stand still and take out the furnace, and remove the mixed salt on the surface after the alloy is solidified. Lower the furnace temperature to 360°C to reheat and melt the solder block, and then pour it into strips on the angle iron for use.

example 2

[0023] Example 2: 26 grams of potassium chloride and 20 grams of lithium chloride mixed salt are poured on 92.5 grams of tin after melting at 460 ° C. Raise the temperature of the furnace to 780°C to melt the tin and the mixed salt, then add 7 grams of Zn to the tin liquid while stirring continuously to form an alloy; use a stainless steel bell jar with holes on the wall to quickly press 0.5 grams of rare earth Er into the Among the above molten alloys, and keep stirring until the rare earth is completely melted. Keep it warm for 1.5 hours and keep stirring to homogenize the alloy. Stand still and take out the furnace, and remove the mixed salt on the surface after the alloy is solidified. Lower the furnace temperature to 380°C to reheat and melt the solder block, and then pour it into strips on the angle iron for use.

example 3

[0024] Example 3: 23.4 grams of potassium chloride and 18 grams of lithium chloride mixed salt are poured on 90.75 grams of tin after melting at 490°C. Raise the temperature of the furnace to 680°C to melt the tin and the mixed salt, then add 9 grams of Zn to the tin liquid while stirring continuously to form an alloy; use a stainless steel bell jar with holes on the wall to quickly press 0.25 grams of rare earth Er into the Among the above molten alloys, and keep stirring until the rare earth is completely melted. Keep warm for 1 hour, stirring constantly to homogenize the alloy. Stand still and take out the furnace, and remove the mixed salt on the surface after the alloy is solidified. Lower the furnace temperature to 360°C to reheat and melt the solder block, and then pour it into strips on the angle iron for use.

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Abstract

The RE containing SnZn-base lead-free brazing alloy for assembling in microelectronics contains Zn 5-9 wt%, Ag 0-1.5 wt%, Bi 3-5 wt% and marketable Er 0.05-1.0 wt% except Sn. The preparation process includes melting mixed salt of KCl and LiCl in the ratio of 1-1.6 to 0.8-1.2 and pouring the molten salt to Sn, melting Sn, adding Zn, Ag and Bi into Sn liquid to melt, pressing Er with holed bell jar into the mixed salt and SnZn-base alloy, rotating the bell jar, maintaining for 1-2 hr, stirring, letting stand and eliminating mixed salt in the surface after solidification. The brazing alloy has fined microscopic structure, low cost, no pollution, convenient smelting, and improved moistening technological performance and metallurgical quality.

Description

technical field [0001] A SnZn-based lead-free solder containing rare earth Er and a preparation method thereof belong to the technical field of lead-free solder manufacturing for electronic assembly in the microelectronics industry. Background technique [0002] In the past ten years, a variety of lead-free solder alloys have been researched and developed at home and abroad, and hundreds of patents are involved. The current research on lead-free solder alloys mainly focuses on three temperature ranges and several alloy series. Among them, the most representative ones are lead-free solder alloys in the medium temperature range, such as Sn-Cu, Sn-Ag, Sn-Zn binary alloys, Sn-Ag-Cu, Sn-Ag-Bi, Sn-Zn-Bi Such as ternary alloys or more alloys. [0003] The basic requirements for lead-free solder should include: the melting temperature should be close to the SnPb eutectic temperature, and the melting temperature interval should be small; there must be good wettability or brazing pr...

Claims

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Application Information

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IPC IPC(8): B23K35/26C22C1/02
Inventor 史耀武郝虎雷永平田君夏志东李晓延郭福
Owner BEIJING UNIV OF TECH
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